Pneumatic power-cylinder.



UNITED STATES PATENT OFFICE.

NILS O. LINDSTROM, OF NEW YORK, BOROUGH OF QUEENS, NEW YORK, AS- SIGNOR TO ALONZO B. SEE AND WALTER L. TYLER, OF SAME PLACE.

PNEUMATIC POWER-CYLINDER.

SPECIFICATION forming part f Letters Patent N0. 671,559, dated April 9, 1901.

i Application filed February 4, 1901. Serial No. 45,847. (No model.) I

To all whom t may COW/007%.' the extension b' to furnish a bearing and guide Be it known that LNILS O.LINDsTROM,a citifor the plug. Surrounding this tail piece and zen of the United States, residing at the city of located in the chamber above the plug is a NewYork, in the borough of Queens and State coiled springl e, which tends to force the plug of New York, have invented certain new and outward or downward and hold its shoulder 55 useful Improvements in Pneumatic Power-` against the collar. The lower face of the pis- Oylinders, of which the following is a full, ton is provided with lugs b2,which are adapted clear, and exact description. to rest against the lower head of the cylinder This invention relates to pneumatic powerwhen the piston is in its lowest position.

1o cylinders, air-cushions, and similar appara- When the piston isin this lowermost position, 6o tus,the object being t0 provide a cylinder and the outer end of the plug covers the inlet-port piston so constructed that the piston can be a' and the plug is almost entirely in the chammoved in one direction by the pressure of air ber b. If air or gas pressure is now admitted against it to perform work and will be free into the port ci from any suitable source, it

to return in the other direction through a cerfirst lifts the plug c a little higher and then 65 tain predetermined portion of its str0ke,while fills the narrow space beneath the entire face during the remainder of the return stroke the of the piston, which is determined by the lugs progress of the piston will be retarded or b2. The piston is then forced upward to the cushioned. end of its stroke to do any work for which the zo The invention consists ot' the construction apparatus is intended. In the upper position 7o hereinafter described and claimed. of the piston it rests again the packing a. and

In the accompanying drawing the figure prevents the escape of air or gas through the represents a central section of the cylinder, vent-hole a2,which otherwise would take place, showing the piston in elevation, with parts since the air or gas will creep past the sides thereof broken away. of the piston, the piston being constructed 75 Arepresentsacylinder; B,apiston adapted with .a small clearance between its annular to move therein. i surface and the walls of the cylinder for a A is the cap or head of the cylinder, on the purpose that will hereinafter appear. The insideof whichisadiska, ofpacking material, return stroke of the piston, which may be 3o against which the piston will rest when at one made by gravityor other power, is permitted 8o end of its stroke. The piston-rod B passes as soon as air o'r gas pressure beneath the pisthrough the cap or head 'of the cylinder, in ton is allowed to exhaust through the port a. which ithas its bearings in the usual manner. The piston will fall with comparative rapid- The opposite end of the cylinder is provided ity until the end of the plug, which is then with an inlet-port a for the air or gas which projecting its full distance below the face of 85 is admitted to the cylinder to lift the piston. the piston, strikes the lower head of the cylin- This port, which is also the exhaust-port, der and closes the escape-portforthe airorgas. is sufficiently large to permit the piston to As there is then no pressure below the plug, fall or return rapidly. In the center of the the passage will be held closed and the air or 4o piston is an axial chamber o, opening at the gas remaining in the cylinder will be trapped 9o lower face of the piston and terminating at and put undercompression to thus retard the the opposite end in a small axial extension further downward movement of the piston.

b. In this chamber is fitted aplug c, having The piston, however, will continue to move a shoulder c' to rest upon a retaining-collar slowly downward as the air or gas leaks past d, secured to the face ofthe piston. The plug the piston and escapes at the Vent above u n- 95- normally projects'through this collar in the til inally the piston comes to rest with its manner shown at its lower or forward end lugs b2 against the lower head of the cylinder and is directed toward and adapted to cover and in the position before described. the port a. The upper or inner end of the The amount of air trapped in the cylinder 5o plug carries a tailpiece c2, which runs into below the piston can be determined by using roo a proper length ofplug c. The longerthe plug the sooner will the cushioning effect take place.

A combined power-cylinder and dash-pot of the character described is useful for various purposes,arnongwhich maybe mentioned;l the operation-of a rheostat for electricalcircuits. The piston-rod may be connected `to` the rheostat and caused to throw the resistance into or out of circuit rapidly on the up-5 stroke of the piston, While on the downstrokeV thereof the said resistance Will be thrown into or out of circuit rapidly for a portion of Lthe stroke, While near the end the stroke Will bel retarded to permit other apparatus tooperate.

Having described my invention, I claim` l. The combination of a cylinder, apiston therein, said cylinder beingprovided with a port which serves both for the inlet and the exhaust, a valve carried -`bythe piston and adapted to close the port at a predetermined point in the stroke of the piston and means whereby said valve Will open under the ifncorning pressure to admit the same to the cylinder for action upon the piston.

2. The combination of a cylinder provided `with fa port which serves both l.for'the inlet and the exhaust, a piston, a valve carried by said piston and having a movement independent thereof and adapted to cover the port yat afpredetermined zpoint in the stroke ,of thepiston, said independent movement permittingthe'pistontocomplete its stroke after the port is covered. 4

3. The combination of a cylinder having a port at one end, a piston provided with a chamber, a plug-valve located in said charnberand-normally projecting therefrom, said ture in presence of ltwo witnesses.

NILS O. LINDSTROM.

l'\7Vitnesses:

WM. A. RosENBAU-M, 'WALDo M. CHAPIN. 

